OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) + 8*a(n-3) + 6*a(n-4) - 4*a(n-5) for n>6.
Empirical g.f.: 2*x^2*(1 + x)*(1 + 3*x - 8*x^2 + 2*x^3) / (1 - 3*x - 8*x^3 - 6*x^4 + 4*x^5). - Colin Barker, Sep 26 2018
EXAMPLE
Some solutions for n=4:
..0..3..0..3....0..3..2..3....0..1..2..3....0..3..0..3....0..3..2..3
..2..1..2..1....0..1..0..1....2..3..0..3....0..1..2..1....2..1..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 03 2013
STATUS
approved